Percutaneous Cryoablation of Renal Tumors: Is It Time for a New Paradigm Shift?

Purpose: To retrospectively assess long-term outcomes of percutaneous renal cryoablation, including factors affecting complications and local recurrence rates. Materials and Methods: A total of 357 computed tomographic (CT) fluoroscopy guided percutaneous cryoablation procedures were performed for 382 masses in 302 outpatients; 347 were biopsy-proven renal-cell carcinoma (RCC) or Bosniak category > 111 masses (n=28). Benign pathologic conditions (n=18) or metastatic non-RCC disease (n=17) were included to analyze procedural complication rate, but recurrence rates, tumor staging, and nephrometry score were limited to RCCs. The average tumor diameter was 2.9 cm (range, 1-10.3 cm), and median nephrometry score for RCC was 8 (mean, 7.4). Protection of adjacent vital structures was performed in 34% of procedures (n=121), and ureteral stent placement was performed for 9.2% (n=33). All major complications were graded per surgical Clavien-Dindo criteria. Results: The average CT-visible cryoablation zone diameter was 5 cm (range, 2.5-10.5 cm). Grade >= 3 complications occurred in 2.8% of procedures (n=10), and appeared related to only high nephrometry scores (P=.0086) and larger tumors (P=.0034). No significant changes in renal function before and after the procedure were noted (P=.18). At a mean follow-up of 31.8 months, the local I tumor recurrence rate was 3.2% (11 of 347) for RCC, and no significant difference was noted between tumors larger or smaller than 3 cm (P=.15). The difference reached significance only among the small number of stage >= T2 RCC tumors (P=.0039). Conclusions: Long-term follow-up of percutaneous renal cryoablation demonstrates low recurrence rates with preserved renal function, even for patients with high nephrometry scores and body mass index, assuming thorough cytotoxic technique and protection measures.